Worm-device



April 1962 w. RODENACKER 3,031,030

WORM-DEVICE Filed Jan. 17, 1958 I /v' I.

INVENTOR. WOLF RODENACKE R A TTORNE YS 3,03Ltl3tl WURM-DEVHCE Wolf iiodenacker, Dormagen, Germany, assignor to Farbenfahriken Bayer Ahtiengesellschaft, Levertrnsen, Germany, a corporation of Germany Filed Jan. 17, 1953, Scr. No. 709,698 Claims priority, application Germany .ian. 22, 1957 3 Qiairns. (Cl. 55--i9tl) This invention relates to a worm device comprising a worm shaft which is sub-divided into a plurality of sectious.

In the case of processes which are carried out in worm devices, such as for example mixing, melting, plasticising, it is often desirable to degasify the material which is to be processed, i.e. to cause the said material to pass through an evacuation zone. Worm machines are known in which two worms are arranged one after the other, one worm delivering into a vacuum container and, separately therefrom, a second worm conveying the material out of the vacuum container. These worm arrangements have separate drives. The delivery of the second worm is adjusted to that of the first worm by arranging for the medium being conveyed to contact a longer section of the second Worm, and thus to increase the pressure and the delivery of the second worm. This method of quantity regulation, however, leads to fluctuations in the quantity of material discharged by the machine, leading to dimensional differences in the material produced which are not allowable where standards are relatively high.

It has now been found that it is possible to obtain a continuous degasification without interrupting the flow of material if at least one section of the worm shaft, used as a degasification zone, is constructed as a cylindrical roller which is surrounded by a housing comprising evacuatable chambers and which, together with the walls of longitudinal ducts in the housing which extend above and below the roller and communicate through apertures with the worm sections forms wedge-shaped gaps. The cylindrical roller forming part of the worm shaft is conveniently arranged between two worm sections. The

material is spread out in a thin layer on the roller by the wedge-shaped gaps and pressed througth the wedgeshaped gaps again into the longitudinal ducts, in which it is conveyed under the pressure of the first worm section into the second worm section. In this way, the material is continuously conveyed through the worm apparatus, so that if a uniform quantity of material is fed in through the first worm section, a uniform delivery is also achieved by the second worm section.

One embodiment of the invention is illustrated diagrammatically in the drawings, FIGURE 1 being a longitudinal sectional view and FIGURE 2 a cross-sectional view on the line 2-2 of FIGURE 1. The liquid substance is introduced through the hole 1 into the worm section 3, in which it is conveyed, according to the direct-ion of rotation of the worm, through the aperture 4 into the degasification zone, which consists of the longitudinal ducts 6 and 7 formed by the housing 2 and the cylindrical roller 5, and of the evacuatable chambers 8 and 9. The walls of the longitudinal ducts 6 and 7 form, together with the roller 5, the wedge-shaped gaps 10, 11, 12 and 13 When the roller forming part of the worm shaft rotates in the direction of the arrow, the liquid conveyed into the longitudinal duct 6 by means of the worm section 3 enters through the wedge-shaped gap at the roller surface in a thin layer into the chamber 8, which is connected by means of the duct 17 to an evacuating device (not shown). The liquid is degasified in the chamber 8 and passes through the wedgeshaped gap 11 under pressure into'the longitudinal duct '7, which is constructed in the same way as the longitudinal duct 6. The longitudinal duct 7 is connected through an aperture 14 to the threads of the worm section 15, so that the liquid mass is fed under pressure into the worm section '15. The worm l5 conveys the material through the hole 16 out of the device. A proportion of the liquid mass is carried from the longitudinal duct 7 through the wedge-shaped gap 12 in a thin layer into the chamber 9 which is also connected by means of a duct 18 .to evacuating means (not shown), and then is fed again under pressure through the wedge-shaped gap 13 into the longitudinal duct 6.

The worm shaft, which consists of the sections 3, 5 and 15, is driven through the agency of the square head connection 21 by the shaft 19, which is sealed by the stuffing box 2t). Thus the worm shaft, sub-divided into three parts, is mounted in freely movable fashion in order that the clearance in the wedge-shaped gaps it), 11, i2 and 13 in the evacuation zone can adjust itself automatically and the liquid mass which is transported in a thin layer on the roller 5 through the vacuum chambers 8 and 9 is not scraped into these chambers. In this way it is possible to dispense with a special surface-representing arrangement with the possible further necessity for measuring devices in the vacuum vessel, and to construct a continuous conveyor worm operating with continuous degasification. Instead of liquids it is also possible to introduce solid substances or plastic masses into the apparatus, which can be melted in known manner in the first section. The method of operation in the evaporation zone is the same. The evacuation zone may also serve, for example, for evaporating a plasticiser as far as a given concentration or for introducing plasticisers, dyestuffs or fillers or the like.

I claim:

1. A worm device for liquid and plastic material comprising a casing having an inlet and an outlet axially spaced therefrom, a worm shaft rotatably mounted in said casing for conveying material axially through the casing from said inlet to said outlet, 2 section of said worm shaft being formed as a cylindrical roller, a portion of said casing laterally adjacent said roller being formed as an evacuatable chamber, means for evacuating said chamber, another portion of said casing circumferentially adjacent said previously mentioned portion defining with said roller a wedge-shaped gap circumferentially leading into said evacuatable chamber, a passage for material communicating said worm shaft and said wedge-shaped gaps, said worm shaft being laterally movable with respect to the casing wall whereby the clearance in the wedge-shaped gap can adjust itself automatically.

2. A worm device according to claim 1 in which said roller is formed on an intermediate section of said worm shaft.

3. A worm device according to claim 2 in which the portion of said casing surrounding said roller defines two opposed evacuatable chambers with two opposed longitudinal ducts circumferentially positioned therebetween, wedge-shaped gaps communicating said chambers and ducts in the direction of rotation of said rollers and passages axially communicating a portion of said worm shaft adjacent said roller with said ducts.

References Cited in the file of this patent UNITED STATES PATENTS 1,283,947 Steinle Nov. 5, 1918 2,595,455 Heston May 6, 1952 2,719,325 Franklin Oct. 4, 1955 2,797,767 Brooke et al. July 2, 1957 2,906,367 Vandenburgh Sept. 29, 1959 

